From Retro To Radiant: 3D Tetris On A LED Matrix

January 21, 2025 by Heidi Ulrich 8 Comments

We love seeing retro games evolve into new, unexpected dimensions. Enter [Markus]’ adaptation of 3D Tetris on a custom-built 3x3x12 RGB LED matrix. Developed as a university project, this open-source setup combines coding, soldering, and 3D printing. It’s powered by an ESP32 microcontroller with gameplay controlled by a neat web interface.

This 3D build makes the classic game so much harder to play, that one could argue whether it’s still a game, or has turned into a form of art. Although it is challenging to rotate and drop blocks on such a small scale, for die-hard Tetris fans (and we know you’re out there), there is always someone up to become best at it. Just look at the FastLED-powered light show, the responsive web-based GUI, and fully modular 3D printed housing, this project is a joy to look at even when nobody is playing it. Heck, a game that turned 40 only a year ago should be so mature to entertain itself, shouldn’t it?

From homemade Pong tables to LED cube displays, hobbyists keep finding ways to give classic games a futuristic twist. Projects like this are about pushing boundaries. Hackaday’s archives are full of similar innovations, but why not craft some new ones?

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Fluid Simulation Pendant Teaches Lessons In Miniaturization

January 13, 2025 by Dan Maloney 7 Comments

Some projects seem to take on a life of their own. You get an idea, design and prototype it, finally build the thing and — it’s good, but it’s not quite right. Back to the drawing board, version 2, still not perfect, lather, rinse, repeat. Pretty soon you look around to discover that you’ve built ten of them. Oops.

That seems to be the arc followed by [mitxela] with this very cool fluid simulation pendant. The idea is simple enough; create a piece of jewelry with a matrix of tiny LEDs that act like the pendant is full of liquid, sloshing about with the slightest movement. In practice, though, this project was filled with challenges. Surprisingly, [mitxela] doesn’t seem to number getting a fluid dynamics simulation running on a microcontroller among those problems, at least not to a great degree. Rather, the LED matrix seemed to cause the most problems, both in terms of laying it out on the 25-mm diameter PCB and how to address the LEDs with relatively limited GPIO on the STM32 microcontroller. The solution to both was diagonal charlieplexing, which reduces the number of vias needed for the 216-LED matrix and allows the 0402 to be densely packed, along with providing some tolerance for solder bridging.

And then there’s the metalworking heroics, which no [mitxela] project would be complete without. This seems to be where a lot of the revisions come from, as the gold-plated brass case kept not quite living up to expectations. The final version is a brass cup containing the LiR2450 rechargeable battery, a magnetic charging connector, and the main PCB, all sealed by a watch crystal. The fluid simulation is quite realistic and very responsive to the pendant’s position. The video below shows it in action along with a summary of the build.

If you want to catch up on [mitxela]’s back catalog of miniaturized builds, start with his amazing industrial ear adornments or these tiny matrix earrings. We’re also fond of his incredible shrinking MIDI builds. Continue reading “Fluid Simulation Pendant Teaches Lessons In Miniaturization” →

Using Audio Hardware To Drive Neopixels Super Fast

January 13, 2025 by Lewin Day 17 Comments

Here’s the thing about running large strings of Neopixels—also known as WS2812 addressable LEDs. You need to truck out a ton of data, and fast. There are a dozen different libraries out there to drive them already, but [Zorxx] decided to strike out with a new technique—using I2S hardware to get the job done.

Microcontrollers traditionally use I2S interfaces to output digital audio. However, I2s also just happens to be perfect for driving tons of addressable LEDs. At the lowest level, I2S hardware is really just flipping a serial data line really fast with a clock line and a word select line for good measure. If, instead of sound, you pipe a data stream for addressable LEDs to the I2S hardware, it will clock that data out just the same!

[Zorxx] figured that at with an ESP32 trucking out I2S data at a rate of 2.6 megabits per second on the ESP32, it would be possible to update a string of 256 pixels in just 7.3 milliseconds. In other words, you could have a 16 by 16 grid updating at over 130 frames per second. Step up to 512 LEDs, and you can still run at almost 70 fps.

There’s some tricks to pulling this off, but it’s nothing you can’t figure out just by looking at the spec sheets for the WS2812B and the ESP32. Or, indeed, [Zorxx’s] helpful Github page. We’ve featured some other unorthodox methods of driving these LEDs before, too! Meanwhile, if you’ve got your own ideas on how to datablast at ever greater speeds, don’t hesitate to let us know!

Blinkenlights-First Retrocomputer Design

January 11, 2025 by Elliot Williams 10 Comments

[Boz] wants to build a retrocomputer, but where to start? You could start with the computery bits, like say the CPU or the bus architecture, but where’s the fun in that? Instead, [Boz] built a righteous blinkenlights array.

What’s cool about this display is that it’s ready to go out of the box. All of the LEDs are reverse-mount and assembled by the board maker. The 19″ 2U PCBs serve as the front plates, so [Boz] was careful not to use any through-hole parts, which also simplified the PCB assembly, of course. Each slice has its own microcontroller and a few shift registers to get the bits lit up, and that’s all there is to it. They take incoming data at 9600 baud and output blinkiness.

Right now it pulls out its bytes from his NAS. We’re not sure which bytes, and we think we see some counters in there. Anyway, it doesn’t matter because it’s so pretty. And maybe someday the prettiness will lure [Boz] into building a retrocomputer to go under it. But honestly, we’d just relax and watch the blinking lights.

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Nottingham Railway departure board in Hackspace

All Aboard The Hack Train: Nottingham’s LED Revival

January 4, 2025 by Heidi Ulrich 4 Comments

Hackerspaces are no strangers to repurposing outdated tech, and Nottingham Hackspace happens to own one of those oddities one rarely gets their hands on: a railway departure board. Left idle for over a decade, it was brought back to life by [asjackson]. Originally salvaged around 2012, it remained unused until mid-2024, when [asjackson] decided to reverse-engineer it. The board now cycles between displaying Discord messages and actual train departures from Nottingham Railway Station every few minutes. The full build story can be found in this blog post.

The technical nitty-gritty is fascinating. Each side of the board contains 4,480 LEDs driven as two parallel chains. [asjackson] dove into its guts, decoding circuits, fixing misaligned logic levels, and designing custom circuit boards in KiCAD. The latest version swaps WiFi for a WizNet W5500 ethernet module and even integrates the Arduino Uno R4 directly into the board’s design. Beyond cool tech, the display connects to MQTT, pulling real-time train data and Discord messages via scripts that bridge APIs and custom Arduino code.

This board is a true gem for any hackerspace, even more so now it’s working. It waited for the exact mix of ingredients why hackerspaces exist in the first place: curiosity, persistence, and problem-solving. Nottingham Hackspace is home to a lot more, as we once wrote in this introductory article.If you don’t have room for the real thing, maybe set your sights a bit smaller.

Do you have a statement piece this cool in your hackerspace or your home? Tip us!

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555 Timers Bring Christmas Charm To Miniature Village

January 2, 2025 by Tom Nardi 10 Comments

The miniature Christmas village is a tradition in many families — a tiny idyllic world filled happy people, shops, and of course, snow. It’s common to see various miniature buildings for sale around the holidays just for this purpose, and since LEDs are small and cheap, they’ll almost always have some switch on the bottom to light up the windows.

This year, [Braden Sunwold] and his wife started their own village with an eye towards making it a family tradition. But to his surprise, the scale lamp posts they bought to dot along their snowy main street were hollow and didn’t actually light up. Seeing it was up to him to save Christmas, [Braden] got to work adding LEDs to the otherwise inert lamps.

Now in a pinch, this project could have been done with nothing more than some coin cells and a suitably sized LED. But seeing as the lamp posts were clearly designed in the Victorian style, [Braden] felt they should softly flicker to mimic a burning gas flame. Blinking would be way too harsh, and in his own words, look more like a Halloween decoration.

This could have been an excuse to drag out a microcontroller. But instead, [Braden] did as any good little Hackaday reader should do, and called on Old Saint 555 to save Christmas. After doing some research, he determined that a trio of 555s rigged as relaxation oscillators could be used to produce quasi-random triangle waves. When fed into a transistor controlling the LED, the result would be a random flickering instead of a more aggressive strobe effect. It took a little tweaking of values, but eventually he got it locked down and sent away to have custom PCBs made of the circuit.

With the flicker driver done, the rest of the project was pretty simple. Since the lamp posts were already hollow, feeding the LEDs up into them was easy enough. The electronics went into a 3D printed base, and we particularly liked the magnetic connectors [Braden] used so that the lamps could easily be taken off the base when it was time to pack the village away.

We can’t wait to see what new tricks [Braden] uses to bring the village alive for Christmas 2025. Perhaps the building lighting could do with a bit of automation?

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Broken USB Lamp Saved With A Bit Of Woodworking

January 1, 2025 by Tom Nardi 1 Comment

For many of us, when we think of creating a custom enclosure, our minds immediately go towards our 3D printer. A bit of time in your CAD program of choice, and in an hour (or several), you’ve got a bespoke plastic box. A hacker’s dream come true.

But extruded plastic is hardly perfect. For one thing, you might want a finished piece that looks a little more attractive on your desk. Which is why we appreciate this quick hack from [Tilma]. When faced with a broken LED light and minimal equipment, he decided to transplant the repaired electronics into a scratch-built wooden frame that not only looks better than the original, but is more functional.

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